Results 11 to 20 of about 1,869 (195)

Die Gattung Erratencrinurus Krueger, 1971 (Trilobita; Ordovizium) aus baltoskandischen Geschieben [PDF]

open access: yesFossil Record, 2004
Aus der mittel- bis oberordovizischen Trilobitenfamilie Encrinuridae, die in Baltoskandia durch die Untergattungen Erratencrinurus und Celtencrinurus repräsentiert wird, werden achtzehn Arten beschrieben, darunter die vier neuen Arten Erratencrinurus (E.)
H.-H. Krueger
doaj   +2 more sources

A persistent influence of supernovae on biodiversity over the Phanerozoic. [PDF]

open access: yesEcol Evol, 2023
It shows the correlation between diversity and supernovae frequency. Abstract It is an open question what has constrained macroevolutionary changes in marine animal diversity on the time scale of the Phanerozoic. Here, we will show that supernovae appear to have significantly influenced the biodiversity of life.
Svensmark H.
europepmc   +2 more sources

Modularity in the trilobite head consistent with the hypothesized segmental origin of the eyes. [PDF]

open access: yesEvol Dev, 2022
The degree and structure of modularity in the heads of two trilobite species, Calyptaulax annulata (left) and Cloacaspis senilis (right) are identified. Best fit hypotheses of modularity are consistent for both species: the eyes and anterior head highly covary (red), consistent with the anteriormost ocular segment of early arthropods.
Vargas-Parra EE, Hopkins MJ.
europepmc   +2 more sources

Developmental traits and life strategy of redlichiid trilobites. [PDF]

open access: yesBiol Rev Camb Philos Soc, 2023
ABSTRACT The developmental mode of four redlichiid trilobites is summarized, based upon exceptionally well‐preserved, articulated specimens from Cambrian Series 2 (stages 3 and 4) strata in southwestern China and South Australia. These relatively complete developmental sequences indicate a balanced rate in segment increase and addition to the thorax ...
Dai T, Zhang X, Peng S.
europepmc   +2 more sources

Systematics, morphology, and appendages of an Early Ordovician pilekiine trilobite Anacheirurus from Fezouata Shale and the early diversification of Cheiruridae [PDF]

open access: yesActa Palaeontologica Polonica, 2021
Pilekiines are the earliest diverging members of the successful trilobite family Cheiruridae. The pilekiine genus Anacheirurus is characterized by sub-quadratic to sub-oval glabella, pitted genae, and a distinct trunk with elongated pleural spines in ...
FRANCESC PÉREZ-PERIS   +3 more
doaj   +1 more source

A new Cambrian catillicephalid trilobite from the Shallow Bay Formation of western Newfoundland, Canada [PDF]

open access: yesActa Palaeontologica Polonica, 2022
Species of Catillicephala are known from sites around the mid-Cambrian margin of Laurentian North America, including Vermont, Quebec, Newfoundland and North Greenland. Catillicephala cifellii sp. nov.
STEPHEN R. WESTROP, ALYCE A. DENGLER
doaj   +1 more source

Floian, Early Ordovician, trilobites from the Olongbluk Terrane, northwest China [PDF]

open access: yesActa Palaeontologica Polonica, 2023
Floian, Early Ordovician trilobites are systematically described and revised based on new material from the middle part of the Duoquanshan Formation of the Shihuigou area, northern Qinghai Province, northwest China.
XIN WEI, ZHIQIANG ZHOU
doaj   +1 more source

A new middle Cambrian trilobite with a specialized cephalon from Shandong Province, North China [PDF]

open access: yesActa Palaeontologica Polonica, 2020
Trilobites achieved their maximum generic diversity in the Cambrian, but the peak of morphological disparity of their cranidia occurred in the Middle to Late Ordovician. Early to middle Cambrian trilobites with a specialized cephalon are rare, especially
Zhixin Sun, Han Zeng, Fangchen Zhao
doaj   +1 more source

Conodonta, Trilobita, and Anthozoa near the Late Frasnian Upper Kellwasser Event of the Geipel Quarry section in Schleiz, Thuringian Mountains (Germany) [PDF]

open access: yesFossil Record, 2003
New recoveries of Trilobita, Anthozoa and Conodonta from the linguiformis Zone close to the Frasnian/Famennian boundary and Immediately preceding the Upper Kellwasser Event level at Schleiz (Thuringia) are investigated.
D. Weyer, R. Feist, C. Girard
doaj   +5 more sources

Trilobites of Thailand's Cambrian–Ordovician Tarutao Group and their geological setting

open access: yesPapers in Palaeontology, Volume 9, Issue 5, September/October 2023., 2023
Abstract Tuff‐bearing upper Cambrian to lowermost Ordovician strata on Ko Tarutao island, Satun province, southernmost peninsular Thailand, contain a rich trilobite fauna relevant to global biostratigraphy, peri‐Gondwanan palaeogeography and shifting evolutionary mode.
Shelly J. Wernette   +3 more
wiley   +1 more source

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